Micro-electro-mechanical systems (MEMS) devices can harvest energy for various applications, such as self-powered or battery-charging devices or systems. Such MEMS devices can harvest energy, for example, by converting mechanical kinetic energy (e.g., environmental vibration) into electrical energy (e.g., electrical charge) and subsequently power a device or charge a battery.
However, there are several limitations to current MEMS energy harvesters. Conventional MEMS piezoelectric devices using a lead-zirconium-titanium (PZT) thin film material to convert energy have environmental and processing tool contamination issues. Conventional MEMS piezoelectric devices using an aluminum-nitride (AlN) thin film material cannot generate larger amounts of power because AlN has a lower piezoelectric coefficient when compared with PZT. Furthermore, conventional MEMS piezoelectric devices are limited to converting kinetic energy from mechanical deformation but not based on structural displacement, velocity, and acceleration (especially when the later three kinds of motion are with zero-deformation, i.e., no deformation).